A WORLD WAR II-era plane flown by a veteran Hollywood stunt pilot plunged into the edge of the grandstands during a popular air race last night.

Three people have been confirmed dead, with more than 50 spectators injured at the National Championship Air Races in Reno, Nevada.

The plane, piloted by 74-year-old Jimmy Leeward, spiralled out of control without warning and appeared to disintegrate upon impact. Bloodied bodies were spread across the area as people tended to the victims and ambulances rushed to the scene.

Authorities were investigating the cause, but an official at the event said there were indications that mechanical problems were to blame.

Stephanie Kruse, a spokeswoman for the Regional Emergency Medical Service Authority, told The Associated Press that emergency crews took a total of 56 injury victims to three hospitals. She said they also observed a number of people being transported by private vehicle.

Of the 56, about 15 were considered in critical condition, 13 were serious condition with potentially life-threatening injuries and 28 were non-serious or non-life-threatening.

The plane

The P-51 Mustang, a class of fighter plane that can fly at speeds in excess of 500 mph, crashed into a box-seat area in front of the grandstand at about 4.30pm local time, race spokesman Mike Draper said.

Houghton said at a news conference that there appeared to be a “problem with the aircraft that caused it to go out of control”. He did not elaborate.

He said the rest of the races have been canceled as the National Transportation Safety Board investigates.

KRNV-TV weatherman Jeff Martinez, who was just outside the air race grounds at the time, said the plane veered to the right and then “it just augered straight into the ground.”

“You saw pieces and parts going everywhere,” he said. “Everyone is in disbelief.”

Tim Linville, 48, of Reno, said the pilot appeared to lose partial control off the plane when he veered off course and flew over the bleachers near where Linville was standing with his two daughters.

“I told the girls to run and the pilot pulled the plane straight up, but he couldn’t do anything else with it,” Linville told the AP. “That’s when it nosedived right into the box seats.”

Linville said after the plane went straight up, it barrel rolled and inverted downward, crashing into an area where at least 20 people were sitting.

“If he wouldn’t have pulled up, he would have taken out the entire bleacher section,” and hurt thousands of people, Linville said.

Linville said the plane smashed into the ground and shattered like an enormous water balloon, sending shrapnel and debris into the crowd.

“It was just flying everywhere,” he said.

Experienced pilot

Leeward, the owner of the Leeward Air Ranch Racing Team, was a well-known racing pilot. His website says he has flown more than 120 races and served as a stunt pilot for numerous movies, including “Amelia” and “Cloud Dancer.”

In an interview with the Ocala (Fla.) Star-Banner last year, he described how he has flown 250 types of planes and has a particular fondness for the P-51, which came into the war relatively late and was used as a long-range bomber escort over Europe. Among the famous pilots of the hot new fighter was WWII double ace Chuck Yeager.

“They’re more fun. More speed, more challenge. Speed, speed and more speed,” Leeward said.

Leeward talked about racing strategy in an interview Thursday with LiveAirShow TV while standing in front of his plane.

“Right now I think we’ve calculated out, we’re as fast as anybody in the field, or maybe even a little faster,” he said. “But uh, to start with, we didn’t really want to show our hand until about Saturday or Sunday. We’ve been playing poker since last Monday. And uh so, it’s ready, we’re ready to show a couple more cards, so we’ll see on Friday what happens, and on Saturday we’ll probably go ahead and play our third ace, and on Sunday we’ll do our fourth ace.”

Houghton described Leeward as a “good friend.”

“Everybody knows him. It’s a tight-knit family. He’s been here for a long, long time,” Houghton said.

He also described Leeward as a “very qualified, very experienced pilot” who was in good medical condition. He also suggested Leeward would have made every effort to avoid casualties on the ground if he knew he was going to crash.

“If it was in Jimmy’s power, he would have done everything he possibly could,” Houghton said.

The National Championship Air Races draws thousands of people to Reno every year in September to watch various military and civilian planes race. They also have attracted scrutiny in the past over safety concerns, including four pilots killed in 2007 and 2008. It was such a concern that local school officials once considered whether they should not allow student field trips at the event.

The competition is like a car race in the sky, with planes flying wingtip-to-wingtip as low as 50 feet off the sagebrush at speeds sometimes surpassing 500 mph. Pilots follow an oval path around pylons, with distances and speeds depending on the class of aircraft.

The FAA and air race organizers spend months preparing for air races as they develop a plan involving pilot qualification, training and testing along with a layout for the course. The FAA inspects pilots’ practice runs and brief pilots on the route and emergency procedures.

Watch raw footage of the plane crash: